Partial molar standard Gibbs free energy

The partial molar excess Gibbs free energy of the methylene group can be used as a means of characterizing stationary phases. From rearrangement of Equation 11.46, an expression for the standard partial molar Gibbs free energy can be obtained. 

For an ideal solution, the total standard partial molar excess Gibbs free energy, AGT, equals the ideal contribution, AG, and AGp = O. In other words, there is no interaction occurring between the solute and the stationary phase. When a nonpolar mole-, cule such as an alkane is chosen as the solute, AG will increase as the polarity of the stationary phase increases. There-—c... 

Since ideal conditions simplify calculations, an ideal gas at 1 atm pressure in the gas phase which is infinitely dilute in solution will be utilized. Then the total standard partial molar Gibbs free energy of solution (chemical potential), AG, can be directly related to KD, the distribution constant, by the expression... 

Another expression for the total standard partial molar Gibbs free energy is obtained from Henry s law. Henry s law may be written... 

The standard partial molar Gibbs free energy of solution is related to the enthalpy and entropy functions at the column temperature T by the expression... 

AGk, AH, AH thus obtained represent the stoichiometric variations of the Gibbs free energy, enthalpy and entropy, respectively, on the transfer of one mole of solute between the two phases in standard state. AG is the same for the hypothetical ideal state and the real state pro wded that the activity equals unity in both. However AHJ is different in the two cases and reference should be made to the hypothetical ideal state. Because the intermolecular attractions which determine AH are identical in the hypothetical (standard) and reference states, AH refers also to the modification of partial molar enthalpy between the reference states. The same conclusion holds true for the modification of molar heat capacities. A/Sk, like AGk, does not apply to the modification of partial molar entropy between reference states but refers to the hypothetical standard state described above. 

ELDAR contains data for more than 2000 electrolytes in more than 750 different solvents with a total of 56,000 chemical systems, 15,000 hterature references, 45,730 data tables, and 595,000 data points. ELDAR contains data on physical properties such as densities, dielectric coefficients, thermal expansion, compressibihty, p-V-T data, state diagrams and critical data. The thermodynamic properties include solvation and dilution heats, phase transition values (enthalpies, entropies and Gibbs free energies), phase equilibrium data, solubilities, vapor pressures, solvation data, standard and reference values, activities and activity coefficients, excess values, osmotic coefficients, specific heats, partial molar values and apparent partial molar values. Transport properties such as electrical conductivities, transference numbers, single ion conductivities, viscosities, thermal conductivities, and diffusion coefficients are also included. 

The symbols and nomenclature are essentially those which have been widely adopted in the American chemical literature however, for reasons given in the text, and in accordance vith a modern trend, the Gibbs symbol fjL and the shorter term chemical potential" are employed for the partial molar free energy. Because atmospheric pressure is postulated for the conventional standard state of a liquid, some confusion has resulted from the use of the same S3rmbol for the standard state as for the liquid at an arbitrary pressure. Hence, the former state is indicated in the text in... 

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